(Mental Floss) -- Each year, America spends about $250 billion on marketing and advertising -- more than the entire GDP of Thailand. Too bad most of that money is a complete waste. For an increasingly savvy, TiVo-equipped public, our brains seem to shut down whenever something registers as "advertising." Which means all those marketing creatives at the big ad firms have had no choice but to, well, get more creative.

"The Blair Witch Project" used a low-budget Internet campaign to create buzz for the movie.

Some advertisers have relied on product placement (think James Bond stopping mid-gunfight for a refreshing sip of Heineken). Others have attempted to make their ads so entertaining that people will watch them in spite of the sales pitch. And then there's the more mischievous route -- the grassroots, take-it-to-the-streets method -- and that's where guerrilla marketing comes in.

Dirt-cheap and chock full of trickery, guerrilla marketing is advertising with a wink. The successful campaigns usually corral attention through subversive means before revealing their true purpose, and they distinguish themselves by being so clever that even once the bait and switch is revealed, there's no negative outcry.

In other words, even though consumers know they've been duped, the reaction amounts to nothing more than a bashful, "Oh Pepsi! We can't stay mad at you!"

And it's with that good-humored and awe-inspired mindset that we pay homage to the best "gotcha" moments in advertising.

1) The Blair Witch Project

Arguably the most important aspect of a successful guerrilla campaign is staying one step ahead of the public. As consumers become more attuned to ad agency efforts, marketers have to figure out how to attack the mob from unexpected angles. The brand standard for catching the public off guard? 1999's The Blair Witch Project. With no stars, no script, and a budget of around $50,000, University of Central Florida Film School pals Daniel Myrick and Eduardo Sánchez successfully scrubbed out the line between reality and fiction.

Don't Miss

The film's tagline set the stage: "In October of 1994, three student filmmakers disappeared in the woods near Burkittsville, Maryland, while shooting a documentary. A year later, their footage was found." Audiences were expected to believe what they were watching -- shaky, low-quality videotape of three runny-nosed kids weeping in the woods -- was an edited-down version of real recovered footage. And while it was certainly an inventive way to challenge the boundaries of cinematic storytelling (not to mention justifying the low-budget look of the film), Blair Witch didn't exactly seem poised to rival Titanic. That is, until an inventive guerrilla marketing scheme was devised.

To ease the suspension of disbelief and stir up some buzz, Sánchez created a Web site devoted to the Blair Witch -- a fictitious, woods-based specter who'd been snapping up Maryland kids for the last century. Although the legend was created out of whole cloth, it was soon snapped up by gullible Interneters everywhere, and a first-ballot hall of fame urban legend was born. Pretty soon, thousands of people were terrified of the Blair Witch. Even when the actors who played the "film students" started showing up (alive) doing interviews about the movie, many across the country refused to believe the Blair Witch wasn't real.

From that point, the "I've got to see for myself" effect took over, and Blair Witch dominated at the box office. Considered the most effective horror hoax since Orson Welles' The War Of The Worlds broadcast, the film grossed $250 million worldwide. Not a bad return for Artisan Entertainment, which paid only $1 million for the flick after its Sundance screening.

2) Médecins du Monde

Not all guerrilla campaigns are about the money. In fact, one of the cleverest and most altruistic grassroots marketing efforts was pulled off by a group called Médecins du Monde -- an international humanitarian organization devoted to providing care for vulnerable populations around the world.

In late 2005, the French branch of the organization staged an extremely effective campaign to draw attention to the plight of the homeless in Paris. Christened the "tent city" initiative, the group distributed some 300 "two-second tents" to destitute Parisians sleeping outdoors. Equipped with the rapid-deploying tents (which didn't require poles or pins), the homeless gathered in small groups of eight to 10 along the Quai d'Austerlitz and the Canal Saint-Martin. The prefab shelter, which bore the Médecins du Monde logo, drew immediate attention to the number of homeless people in the area and provoked such incredible public outrage that the city was forced to act. A rare off-season government session was convened, and officials admitted that Paris' homeless shelters were vastly overcrowded. They immediately announced the allocation of nearly $10 million for emergency housing.

3) Half.com

The thing about Internet domain names is that they're frequently difficult to remember. They have "krayzee" spellings, or "numb3rs" in them, or they're only tangentially related to the products they offer. (What does "fogdog" have to do with sports equipment, anyway?) And in 1999, name recognition was one of the main problems facing half.com, an eBay-esque online marketplace that allows people to sell used items for fixed prices without the hassle of an auction. "There is such a dot-com clutter out there," half.com CEO Joshua Kopelman said at the time. "We wanted to do something innovative to get some visibility in the crowd."

That something turned out to be giving the 360-person town of Halfway, Oregon, $100,000 and a new computer lab to rename itself half.com for one year. When media outlets picked up the story, half.com (both town and Web site) got some much-needed publicity. Within weeks of its launch, the site was covered by the Today show, The Wall Street Journal, and The New York Times. Time magazine even called the renaming arrangement "one of the greatest publicity coups in history."

The man who literally put half.com on the map was the site's then VP of marketing, Mark Hughes. Hughes, who is now proprietor of buzzmarketing.com, managed to generate so much publicity for half.com that only three weeks after the renaming was announced, eBay snapped it up for a cool $313 million. And while half.com is probably the most successful town/product renaming event in history, it's not the only one. In 1950, Hot Springs, New Mexico, rechristened itself Truth or Consequences after a popular game show, and in 2005, Clark, Texas, decided to go by DISH, Texas, in exchange for a decade of free satellite TV.

4) Acclaim Entertainment

Nowhere are the semi-criminal aspects of guerrilla marketing more important than in pitching to videogamers. Regular folks might occasionally enjoy being duped by an unusually clever campaign, but gamers seem to suck down daring and deception like a Big Gulp of Mountain Dew. The more the stunts flaunt the law, the more the gaming demographic seems to like them.

The undisputed high-score holder in this renegade arena is Acclaim Entertainment, a plucky little company that began as a one-room outfit in Oyster Bay, New York, and bloomed into a multinational juggernaut. Eschewing artistry in favor of an "all publicity is good publicity" philosophy, Acclaim stirs up the stuffy types -- and then laughs all the way to the bank. One of its bedrock tactics is to offer people money for performing some insane stunt on behalf of its upcoming game. Prior to the release of "Turok: Evolution," for instance, the company offered £500 to the first five U.K. citizens who'd legally change their names to Turok. (Almost 3,000 people tried to claim the prize.) Later, promoting the release of "Shadow Man 2," Acclaim announced it would pay the relatives of the recently deceased to place promotional ads on the headstones of their dearly departed. The company said the promotional fee might "particularly interest poorer families."

The latter campaign was, of course, shouted down. But Acclaim blew it off and said the whole thing was a joke -- right after its name had been conveniently plastered all over the headlines. In fact, many of the company's schemes are designed to die on the vine that way. Acclaim actually counts on law enforcement and city officials to shut down their antics -- preferably as publicly as possible. In 2002, the company announced its plans to promote "Gladiator: Sword of Vengeance" using something called "bloodvertising." Touting it as the bloodiest game of all time, Acclaim said it was developing bus shelter ads that would seep a red, blood-like substance onto city sidewalks throughout the course of seven days. Officials thought that might not be in the best taste, so the campaign was aborted, as the world looked on. Also in 2002, Acclaim offered to pay all speeding tickets incurred in the U.K. on the day its racing game "Burnout 2" was released. Naturally, the bobbies balked, feeling that removing the consequences for speeding might encourage people to speed. Acclaim judiciously rescinded the offer, but, yet again, not before the name "Burnout 2" was burned into the public consciousness.

5) Vodafone

While some guerrilla campaigns border on art -- baffling consumers with their cocky blend of ingenuity and imagination -- others take a more boorish approach. During the 2002 Bledisloe Cup rugby match, for example, two young men suddenly burst onto the field at a crucial moment and ran across the pitch wearing nothing but the Vodafone logo painted on their backs.

Admittedly, streaking at a rugby match isn't exactly uncommon, but sponsored streaking very much is. Adding to the drama? The fact that the match was held in Telstra Stadium -- Telstra being Vodafone's competitor.

In the end, one of the streakers was fined $3,500 (AUS), and a maelstrom of criticism was directed at Vodafone. However, millions of TV viewers witnessed the event live, and it was covered everywhere from CNN to the front page of the The Times in London. For a company seeking to sell itself as young and brash, such backlash was a ringing endorsement.

6) Obey: Andre The Giant Has A Posse

Most marketing ploys are created to promote a product, but the global rash of stickers, posters, and stencils reading "Andre The Giant Has A Posse" exist only to urge people to question their surroundings. In essence, it's an ad campaign against advertising.

As subversive as it is pervasive, what became known as the "Obey Giant" campaign began when Rhode Island School of Design art student Shepard Fairey made a bunch of stickers and started putting them up around Providence. Mimicking Soviet-style propaganda posters, the stickers featured the unlikely visage of late professional wrestler Andre "The Giant" Roussimoff accompanied by messages like "Obey" and "Andre the Giant Has A Posse." The stickers' message was unclear -- yet clearly counterculture. It resonated with local skateboarders, rockers, and other underground types, and soon, many were asking to join in the fun. The stickers spread underground to New York, Los Angeles, and Boston, and within a few years, they were all over the world.

The Obey Giant campaign is the kind of thing that, once you see it for the first time, you start to see it everywhere. The stickers are hip and cryptic, and they capitalize on the fact that most people think it's cool to be part of something not everyone understands. Beyond that, the campaign does have a high-minded mission -- to create a kind of emptiness in the observer. The propaganda orders a person to do something ("obey"), but the viewer doesn't know what to do or how to obey. Fairey hopes this confusion will make people question other directives they receive visually -- namely, in ads.

These days, Fairey heads up a design and marketing company that reps youth-targeted brands, such as Pepsi and Universal Pictures. An anti-advertising ad campaign staged by a big-shot advertiser? It doesn't get much more guerrilla than that.E-mail to a friend